Internally fired water tube type boiler



Feb.y 18,1941. c, yE MARSH INTERNALLY FIRED WATER TUBE TYPE BOILERV Filed Feb. 6, 19259 4 Sheets-Sheet l vM'E'fD Feb. 18, 1941.' v c, E, MARSH l 2,232,546 INTERNALLY'FIRED WATER` TUBE TYPE BOILER Filed Feb. 4s, 19:59 4 sheets-sheet 2 Falo 18, 1.941. c, E. MARSH INTERNALLY FIRED WATER TUBE TYPE BOLER 4 Sheets-Sheet 5 Filed Feb. 6, 1959 Feb. 18, 1941. cnE. MARSH 2,232,546

INTERNALLY FIRED WATER TUBE TYPE BOILER Filed Feb. 6, 1959 4 sheets-sheet 4 @LT-Eji- UNITED `STATES PATENT OFFICE INTERNALLY FIRED WATER TUBE TYPE BOILER Cloyd E. Marsh, Wichita, Kans., assigner to The Watson Water Tube Boiler Company, Inc., Wichita, Kans., a corporation' of Kansas Application February 6, 1939, Serial N0. e254,815 Claims. (Cl. 122148)` This invention relates to an internally red vention will beapparent from the disclosures in water tube type boiler, and more particularly to the specification and the -accompanying drawings.

certain improvements over the construction of 'This invention (in its preferred form) is illusboiler disclosed in the Watson Patent No. trated in the-drawings and hereinafter more fully 5 2,110,432, dated March 8, 1938. described. 5

Through extended research on the effect of On the drawings: constructional changes, I have been able greatly Figure 1 is a side elevational view of a boiler vto increase the efciency and practicability of the installation embodying the prin'ciple's of my type of. boiler shown in. that patent. One of the invention.

novel features of construction embodying my AIgule 2iS-a'101181211d1'1a1 SeCtiOnal View 0f the 10 present invention is the provision of a removable boiler shown in Fig. 1, with parts brok-en away uni-tary heating element assembly mounted from and parts in elevation.

the front head of .the boiler shell and having at `Figure 3 isa sectionalv view taken substantially its rear end a dependent roller resting directly along the line III--IIIof Fig. 2. upon the shell. This arrangement makes it pos- Figure 4. is-a sectional view taken substantially 15 sible to roll out the enti-re heating element assemalong the broken line IV-IV o'f Fig. 2.

bly by simply unbolting the front head of the `Figure 5 is an enlarged, broken sectional View boiler. However, even this simple operation is `taken. substantially along the broken line V-V rendered unnecessary in most instances, because of Fig. 3, with parts in elevation.

of other novel features of construction that perv Figure 6i is an exploded, or diagrammatic View, 20 mit the cleaning and replacement of the water illustrating the .path of flow of ycombustion gases tubes without removal of the heating element and of boiler feed Water. assembly. Figures 7 and 8 are elevational views of the i A feature contributing to the high heat eifront and rea-r heads, respectively, of the boiler v ciency of my boiler is the provision of a plurality shell.

of concentric shells, or jackets, about the boiler As shown `.on the drawings: shell to .dei-lne an intermediate gas space for the The reference numeral l0 (Figs. 1 and 2) inpassage oi waste ue gases and an outer water T dicates generally an internally flredwater tube space within which feed water for the boiler may type of boiler embodying lthe principles of my l 30.12 preheated by absorption of the residual heat invention. Said Vboiler I0 comprises a vlower 30 t combustion chamber above the Water tube casing charge connection into an air duct I8, which lat- 4f of the. flue gases before being vented to a stack. steam `generating unit Il, mounted in a rear- By this arrangement the temperature. of the flue wardly and. upwardly inclined position upon supgases entering the stack is brought to a very low porting members l2, and an upper steam sepapoint, such` .that a very large proportion of` the rating unit i3.. connected to said steam generating 1 latent heat of vaporization of the steam resulting unit il by va downt'ake pipe i4 adjacent the 'front 35 from the. combustion of hydrogen in the fuel. can endi'o'f the boiler and an uptake pipe I5 adjacent be utilized in the preheating of the boiler feed therear endof the boiler. water. To` the best of my knowledge, it has not The .boiler of my invention is particularly heretofore been possible in steam boiler conadapted to burn liquid or gaseous fuels, such as 40 struction to utilize sucha large proportion ofthe oil or gas. As illustrated, the boiler l0 is shown 40 sensible and latent heat of the gaseous products with an oil burner, indicated generally by the of combustion as is accomplished by the operation reference numeral |15.` Said` oil burner i6, which of my boiler. may be of conventional or any suitable construc- I- have also been enabled, by positioning the tion, comprisesanair mower l1 having a disand by a novell vbaille arrangement,` to increase ter also serves .as a housing for a burner nozzle greatly the velocity -of conve'ctional flow of water I9, .into which Voil is introduced through a pipe through the Iboiler system, and hence the heat 20 having a valve 2|. A pair of electrodes 22, efli'c'iency of theb'oi'ler. connected" to a suitable source of electrical *cur- It is therefore an important object ofl this inrent by means of `leads 23,. serves to ignite the 50 vention to provide an internally red Water tube air-fuel mixture when starting up the burner. type boiler of improved construction embodying The Vair intake for the blower' l1 comprises a the novel features to which reference has been conduit 24 extending into" a housing 2l5 .posimade above.- tionecl'4 at the `frontend' oftheboiler and serving 55. Other yan'd further important objects of this ina.- purpose that will later be explained. 55

The steam generating unit II comprises an inner cylindrical boiler shell 26 (Fig. 2) having flanged ends 21 and 28 at the front and rear of the boiler, respectively. A plate 29 is bolted to the rear flange 28, as by means of bolts 30, to constitute a closed head therefor. At the front end, a similar plate 3| is bolted.. to theflange 21 by means of bolts 32 to constitutefa removable front head for the boiler.

Within the shell 26 is mounted a removable unitary heating element assembly, indicated gen! erally by the reference numeral:`33.`Said assembly 33 comprises a cylindrical combustion tube or casing 34 `and a plurality ofwaterltubecasings, such as the pair of casings'35`andl`36f-gFigs. 3. and 4). In large installations, tWQgGQmbUStion tubes may be employed and the number of water tube casings may be increased as required: Said water tube casings 35 and 36 are connected near their rear closed ends to the combustion tube 34 by means of relatively short, `curved conduits 31 and 38, respectively. Said lconduits enter the cylindrical walls of said water :tubel casings at points spaced slightly from their rearenis s0 that the hot combustion gases do not impinge directly against the tube ends. The'life lofthe water tubes is lengthened by my arrangement. The water casings 35 and 36"-area`t a lower level thanV that of the combustiontube casing 34 and the axes of all three are preferablysymmetrically arranged with respect to a cominon center. The rear end of the heating assembly 33 issupported upon a carriage 39 havingladependent forked bracket 40 in which is journaledi a roller 4| that rests directly upon the inr'ierrvcallv of the shell 26. At its front end, the combustion Acasing 34 extends through the front head`3'I (Fig.'5) and is provided with an integral inner annular flange 42. Said flange 42 abuts against the front head 3| and is secured thereto'vby bolts '90 passing through an outer flanged fitting 42a, the head 3| and said flange 42. Saidouter'itting 42a hasv a, flanged opening 43 adapted tojtelescopically receive the end of the air duct I8 ofthe burner` I6. Each of the water tube casings 35`and 36isv connected by means of ,branch cpndui'tsfM and 45,' respectively, with a main 'conduit' '46 vthat extends outwardly through thefront plate `3|` and is secured in said plate 3| by means of inf side and outside flanges. 41. The projecting end 48 of said outside flange 41 sia'daptedfgto telescopically receive a returnV bend conduit '49, which will later be described@ y From the foregoingfdescription it`will'be' apparent vthat the unitary h eatingfelement.v assembly 33 may readily be removed,either entirely or partially, for inspection or repairs by merely unfastening the. bolts 32 and rollingpthe assembly outover the interior' of the'shell 26; However, it'

i's not generally necessary f or most purposes evenv to Vremove the heating elementi: assembly. As shown in Figs. 7 and 8, both the front. and` rear heads are provided with pairs o fjrernovable manhole covers 9| and 92, respectively,`fwhich arein alinement with the water tube casings 35 and '36, so that it is a relativelysimplematter to 'insert rotary tube cleaners through the openings 4pro-f vided when said covers are removedz and clean out the water tubes. If a' lwater tube has to be removed, the rearr head 23 can befuribolted :and removed, and a worker can enter the'bo'iler shell through the rear end. Alternatively; or. in addi'- t'on @to removing the rear head, .the front 'head 3| and the flanged fittings 42'affand141 maybe unbolted, and the front head moved awaysuinciently to permit entrance of a worker through the opening so provided.

When in position within the boiler, the rear end of the assembly unit 33 is entirely supported by the roller 4I from the shell 26. 'Ihis arrange- 5 ment compensates for expansion and contraction of the unit without any strain upon the metal. rI he front end of the assembly unit 33 issecured in and supported by the front head 3| of the boiler so as to be removable therewith, as already 10 described. No other means for supporting the heating element assembly 33 is required, but a baille 50 is provided that does, in some measure, serve to support the forward ends of the water .tube casings 35 and 36 from the combustion cas- 15 ing 34. y

Said baffle 56 comprises -a circular plate having openings for receiving said casings 34, 35 and 36 and having a lower cut out portion 5|. The bale 50 is preferably positioned at a slight inclination 20 downwardly and forwardly so that its top edge is rearwardly of the downtake pipe I4 l'and its lower 'edge is rearwardly of the conduits 45 and 44. The cut out portion 5| permits the convec` tional ow of water through the boiler from the 25 front to the rear, as will be more fully described hereinafter. As best shown in Figs. 3, 4 and 6, a pair of' segmental cylindrical plates 52 and 53, concentricwith the inner boiler shell 26, are mounted upon# opposite sides thereof in spaced rel-ation to said shell 26 to form gas spaces 54 and 55, respectively.

Said plates 52 and 53 do not extend for the full length of the boiler shell 26 but terminate near the rear end as at 56 and near the front end as 35' at 51 (Fig. 1). As a matter of economy in the construction of the boiler, the plates 52 and 53 do not extend completely about the circumference of the shell 26 but are spaced apart at the upper side of the shell by a distance somewhat greater 40T 26.; Similarly, the plate 52 is provided along its 50- lower edge with a spacing ange 56 and the plate 53 along its lower edge with a spacing flange 60, between which there is appli-ed a layer 6I of insulation material to protect the boiler shell 26.-

Each of the plates 52 and 53 carry a plurality 55 of' longitudinally extending ribs 62 and 63, respectively, which may suitably be angle irons welded to said plates 52 and 53. Said angle irons 62 and 63 have radially projecting ylegs of sufficient width to project against the outer surface 60- of the boiler shell 26 and thus partition off the gas spaces 54 and 55 into parallel channels. As best shown .in Fig. 6, the ribs 62 do not extend the full length of the plate 52, but are soarranged as to provide a serpentine path for the flow of gases from one end of the boiler to thel other and back again in a plurality of horizontaly passes. The ribs 63 are similarly arranged with respect to the plate 53,

The return bend conduit 49, which was previously'described as being connected to the main gas conduit 46 from the water tube cas'lngs 35 and 36, is provided with two branches, one branch 64 being connected into a fitting 65 mounted ex-I ternlally upon the lower front face of the plate 15.

52;,'andt'he other branch 66 connected to a similar tting 61 mounted upon the lower front face of the plate 53. Since the arrangement issyrnmetical' with respect Ito the Vertical plane passing lthrough the axis of the boiler, only one of the gas conduit connections need be explained'.`

Asbest shown in Fig. "6, the gas conduit 64 enters the external litting 65, which opens inlto the lower horizontal path, designated by the letter A, formed 'by the lower rib 62 within the gas space 55', The flow of gases is in the direction of the arrows, around the end of the lower rib 62 and alongjthe intermediate path B toward the forward condensate drain pipe 68 is positioned at the lowerinost'forwardcorner of the plate 52 to drain any water fromv theI gas space 54 that may be condensed out of the flue gases.

A second palr of concentric plates 69 and 10 are positioned about the plates 52 and 53, respective1y,in spaced relation thereto to provide water spaces 111 .and 112, respectively (Fig. 4). The plates 69:andv10 `being identical, the-construction of plateiBB alone will be explained- Said plate 69 (Fig 6) isproviided with la marginal inturned flange 1-3fexte'nding around all four edges there# ofand' arran'gedt-o t tightly against the y'ru'ter surface-ofthe plate 512. A feed water intake pipe 114 enters the plate 69 near the rear upper corner thereoffor the introduction of boiler feed walter inftothe walter space 1I. The cold feedwater passes intothe water space in .a generally downward-direction, as indicated by arrows in Fig. 6, and thence, as it becomes heated, flows upwardly toward the forward end of the boiler, from which a pipe 15 serves t'o conduct the preheatedwater into 'the downtake pipe I-4. The pipe 15 is branched land the other branch connected t-o the water space on the other side of the boiler shell. Owing to [the relatively flow temperature .to which thefeed Walter is preheated in the outer jacketed waiter spaces, it is not necessary to insulate the body of the steam generating unit, although this rnay be done if desired, and particularly Where there is a return condensate feed to the boiler.

Returning now to a more speciiic description of 'the heating element assembly, the combustion lcasing .34 (Fig. 5) is provided at its front end with a lining 1-6 of refractory material. Said lining 116 extends for a sufficient dis-tance from the front end of the casing to protect the metal of the casing from the high :temperatures developed within the primary combustion area of the fuel. The inside diameter of the combustion casing 34 is of sufficient dimension, and the casing of suflicient length, for substantially complete combustion of the fuel to take place before .the gaseous produots of combustion leave the rear end of the combustion tube through the connecting conduits 31 and 38. 'Ihe rear end of the combustion casing 314 is closed by a p-lalte 11, which may suitably be y welded therein,

Each of the water tube casings 35 and 36 being identical, only one need be described. The water tube casing 35 (Fig. 5) comprises a cylindrical casing headed at its front and rear ends by means of plates 118 and 1l9, respectively, which plates are apertured to receive water tubes 80. 'Said `water tubes extend through the plates 18 .and 19 and are suitably secured therein. The gla'seous products of combustion entering the water tube casings 35 and 3I6 through the pipes 31 and 38 traverse the ffull length offsuch water tube oasings and are discharged from the front ends thereof `through the connecting conduits 44 and 45 and collected in the main gas conduits 46 ex` tending through the front head 3| of the boiler'.

The external return pipe bends 64 and 66, for a portion of their length, are encased within the housing 215 (Fig. 1) and there serve indirectly to prehealt the air within said housing 25 that is drawn into the blower I1 and mixedfwith the fuel within the combustion chlamber 314. A higher efficiency "of combustion is thus obtained by this provision for the prehealting of the air going to Ythe combustion chamber. I

The upper steam separating unit |53 is provided with the usual accessories, such as a water glass 8II, aiglauge 82 mounted thereabove, a pressure control device 83 and a safety valve 8l4 for indicating when the pressure in the `unit becomes excessive.` Steam is drawn off from the steam separating unit I3 through a pipe rt5 having la y valve 81.6 therein.

i The operation of vthe boiler is as'follovvs:v The `blower I1 is started up and oil admittedf through the pipe 2U under suffi-cient pressure to eifect atomizaltion in passing through the burner nozzle IES. Ignition of the oil is accompLlislhedby the sparks set up between the terminals of the electrodes 2 12. Primary combustion of the fuel takes place within the refractory lined portion of the combusti-on tube 34. Under the llight pressure of theblower, the gaseous products of combustion are caused yto pass from the combustion chamber 34 through the gas conduits 31 and 38 into'the interiors of the walter tube casings 35 and 36. 'Ihe casings and connecting conduits are so proportioned that there is no substantial reduction in the velocity of the combustion gases as they pass from the combustion casing :through :the gas conduits 31 and 38 n-to the water tube casings 35 and 36.

The" combustion gases flo-w through said Water tube casings 35 and 36 in a direction counter to that of the flow of water through the tub'es- 8U; The rapidity of iiow of the water through said tubes 8D is increased by reason of the inclination of lthe heating element assembly upwardly Itoward the rear of the boiler, and also by reason of the fact .that the gaseous products of com#v bustion are at their highest temperature when they enter saidwater tube casings at their higher, rear ends.

From thewater tube casings 35 and 36, the gaseous products of combustion flow outwardly at the front ends of said casings through the branch pipes 44 and 45 into the main gas conduit 46 and thence through the external return bends 64 and 66 into the fittings 65 and 61. The waste gases then pass through the bailled gas spaces 54 and 55 in the series of horizontal passes A, B and C that extend substantially the full length of the boiler shell, before being discharged through the vents 610 to the stack.

Boiler feed water is introduced into the water spaces 1I and 12 through the feed intake pipes 14 into heat exchange relationship with the ex haust gases passing through the gas spaces 54 and 55. The flow of the feed Water is downwardly and rearwardly through the water spaces 75 II and 'I2 and thence upwardly into the pipes 15 that join and enter the downtake pipe I4. Drain pipesv 81 are provided for draining the water spaces II and 12. y

Within the boiler, the general flow of water is downwardly through the downtake conduit I4 into the front end of the lower steam generating unit I I and rearwardly through the cut-away portion 5I of the baiile 50. As the water passes beyond the baflie 50 toward the rear end of the boiler, it flowsupwardly around the several casings 34, 35 and 36 of the heating element and is heated thereby. An even more rapid flow of water, however, occurs through the tubes 80 of the water tube casings 35 and 36, the water entering at the front ends of said tubes and owing upwardly and rearwardly into the space between the rear head 29 of the boiler and the rear ends of said water tube casings. From this rear space, the heated Water rises through the uptake conduit I5 into the stream separating unit I3.

"Ihere is a general forward flow of water within the steam separating unit I3 toward the downtake pipe I4. 'Ihe water within said separating unit I3 is maintained at substantially the level indicated in Fig. 2. Steam is withdrawn through the pipe 85 as required.

Although the boiler has been described in connection with the generation of steam, it will be understood that it can be used as a hot water boiler, or for the heating or evaporation of other liquids. The boiler is, however, particularly designed for the generation of steam and for this purpose exhibits a very high degree of efiiciency.

It will, of course, be understood that Various details of construction may be varied through a Wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

v 1. In an internally red water tube type boiler, a unitary removable heating element assembly comprising a combustion casing, a plurality of Water tube casings having headed ends and Water tubes extending therethrough, gas conduit means connecting the inner ends of said casings to position said Water tube casings at a lower level than said combustion casing, means supporting the 'inner ends of said casings for rolling movement over the interior of said boiler, a plate constituting a head for said boiler supporting the outer end of said combustion casing, a branched gas conduit connected to and extending from the outer ends of said water tube casings through said plate and secured therein to support said outer ends from said plate and a baffle plate car-l ried by said casings adjacent the outer `ends thereof Vand positioned inwardly of said branched gas conduit connection, said baille having a lower cut-out portion to facilitate the convection iiowv of water through said boiler.

v2. In a boiler of the internally red water tube type, a cylindrical boiler shell, concentrically curved plates spaced outwardly about said s,hell toV define a gas space and longitudinally extending ribs spacing said shell and plates and arranged to create a serpentine path for the gases through said space, each of said plates having openings for the introduction of gases into the lowermost rim of said serpentine path.

3. In a boiler of the internally fired water tube type, a cylindrical boilen shell, concentrically curved plates spaced outwardly about said shell to dene a gas space and longitudinally extending ribs spacing said shell and plates and arranged to create a serpentine path for the gases through said space, said ribs being more closely spaced toward the gas exit end of said path to aord a gas path of progressively decreasing cross-sectional area to thereby maintain a substantially constant velocity of flow of said gases while said gases undergo contraction due to cooling.

4. An internally fired water tube boiler, comprising a lower steam generating unit, an upper steam separating unit, a water uptake joining the rear ends of said units, a water downtake joining the front ends o-f said units, said steam generating unit having jacketed walls providing an intermediate gas space and an outer water space, a pipe connection for introducing feed Water into said water space to be preheated and a conduit for conducting preheated water therefrom into said downtake.

5. An internally fired water tube boiler, comprising a lower steam generating unit, an upper steam separatingunit, a water uptake joining the rear ends of said units, a water downtake joining the front ends of said units, said steam generating unit having jacketed walls providing an intermediate gas space and an outer Water space, a pipe connection for introducing feed water into said Water space to be preheated, a conduit for conducting preheated water therefrom into said downtake, a heating element assembly within said steam generating unit, a conduit for conducting heated gases therefrom into said gas space at a point remote from said feed Water pipe connection and a vent for said gases positioned adjacent said feed water pipe connection.

CLOYD E. MARSH. 

